Polygamous marriage is widely practiced in our country. About 14% of currently marriedrnwomen are in polygamous union with marked regional variations. Although polygamy isrnwidely practiced, there are very few studies on its health or economic consequences. Arntotal of 692 currently married women (226 in polygamous and 466 in monogamousrnunion) aged 15-49 were selected in the Meskan and Mareko District southern Ethiopiarnusing multistage systematic random sampling. Qualitative and quantitative methods werernused to collect data. The study aimed at examining the effect of polygamous marriage onrnthe nutritional status and reproductive health women. In addition the study tried torncompare the two groups of women in terms of their socio-demographic & economicrncharacteristics, decision making power, occurrence of diseases and health seekingrnbehavior, nutritional status and selected elements of reproductive health. Result showedrnthat women in polygamous union were more affected by chronic energy deficiencyrn(CED) compared to those in monogamous union. [AOR (95% CI) : 1.55 (1.08,2.22).rnHowever attendance of ANC and use of family planning were not found to bernsignificantly different between the two marriage forms (polygamous and monogamous).rnUrbanization and literacy of both women and husbands were the factors identified to bernaffecting both the nutritional status and reproductive health of women. More women inrnpolygamous union were older in age, Moslem, illiterate and had previous marriagesrncompared to those in monogamous union. Polygamous husbands were illiterate, farmersrnand had more number of children compared to monogamous husbands, which wasrnsignificant. Although women in polygamous union possessed farmland they were at riskrnof having farm product insufficiency. On the average women in polygamous unionrnviirncompared to those in monogamous union got married earlier (mean age at first marriagern15.8 Vs 16.3), had larger number of pregnancies (5.61 Vs 4.8) and deliveries (5.3 Vs 4.7)rnwhere the observed differences were significant. The decision making power were atrnlargely under the husbands'. Women in polygamous union seemed to exercise morerndecisions making compared to women in monogamous union except for major decisionsrnwhere the difference became negligible. In conclusion women in polygamous union werernat socio-demographic, socioeconomic, nutritional and reproductive health disadvantages.rnHence there is a need to discourage polygamy through religious leaders, communityrnparticipation and involvement of other related sectors. Urban residence and enhancing therneducational level of both men and women are the key factors in improving both thernnutritional and reproductive health states of women.